<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Phrase.php 16541 2009-07-07 06:59:03Z bkarwin $
 */


/**
 * Zend_Search_Lucene_Search_Weight
 */
require_once 'Zend/Search/Lucene/Search/Weight.php';


/**
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Search_Lucene_Search_Weight_Phrase extends Zend_Search_Lucene_Search_Weight
{
	/**
	 * IndexReader.
	 *
	 * @var Zend_Search_Lucene_Interface
	 */
	private $_reader;

	/**
	 * The query that this concerns.
	 *
	 * @var Zend_Search_Lucene_Search_Query_Phrase
	 */
	private $_query;

	/**
	 * Score factor
	 *
	 * @var float
	 */
	private $_idf;

	/**
	 * Zend_Search_Lucene_Search_Weight_Phrase constructor
	 *
	 * @param Zend_Search_Lucene_Search_Query_Phrase $query
	 * @param Zend_Search_Lucene_Interface           $reader
	 */
	public function __construct(Zend_Search_Lucene_Search_Query_Phrase $query,
	Zend_Search_Lucene_Interface           $reader)
	{
		$this->_query  = $query;
		$this->_reader = $reader;
	}

	/**
	 * The sum of squared weights of contained query clauses.
	 *
	 * @return float
	 */
	public function sumOfSquaredWeights()
	{
		// compute idf
		$this->_idf = $this->_reader->getSimilarity()->idf($this->_query->getTerms(), $this->_reader);

		// compute query weight
		$this->_queryWeight = $this->_idf * $this->_query->getBoost();

		// square it
		return $this->_queryWeight * $this->_queryWeight;
	}


	/**
	 * Assigns the query normalization factor to this.
	 *
	 * @param float $queryNorm
	 */
	public function normalize($queryNorm)
	{
		$this->_queryNorm = $queryNorm;

		// normalize query weight
		$this->_queryWeight *= $queryNorm;

		// idf for documents
		$this->_value = $this->_queryWeight * $this->_idf;
	}
}


